[PATCH v4] coccinelle: api: add kvmalloc script

From: Denis Efremov
Date: Wed Sep 30 2020 - 12:01:15 EST

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Suggest kvmalloc, kvfree instead of opencoded patterns.

Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
Changes in v2:
- binary operator cmp added
- NULL comparisions simplified
- "T x" case added to !patch mode
Changes in v3:
- kvfree rules added
Changes in v4:
- pattern updated to match only GFP_KERNEL/__GFP_NOWARN flags
to avoid possible false-positives

All patches are sent:
[1] https://lore.kernel.org/patchwork/patch/1296428/
[2] https://lore.kernel.org/patchwork/patch/1296636/
[3] https://lore.kernel.org/patchwork/patch/1282895/
[4] https://lore.kernel.org/patchwork/patch/1296631/

scripts/coccinelle/api/kvmalloc.cocci | 256 ++++++++++++++++++++++++++
1 file changed, 256 insertions(+)
create mode 100644 scripts/coccinelle/api/kvmalloc.cocci

diff --git a/scripts/coccinelle/api/kvmalloc.cocci b/scripts/coccinelle/api/kvmalloc.cocci
new file mode 100644
index 000000000000..c30dab718a49
--- /dev/null
+++ b/scripts/coccinelle/api/kvmalloc.cocci
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Find if/else condition with kmalloc/vmalloc calls.
+/// Suggest to use kvmalloc instead. Same for kvfree.
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+
+virtual patch
+virtual report
+virtual org
+virtual context
+
+@initialize:python@
+@@
+filter = frozenset(['kvfree'])
+
+def relevant(p):
+ return not (filter & {el.current_element for el in p})
+
+@kvmalloc depends on !patch@
+expression E, E1, size;
+identifier flags;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier x;
+type T;
+position p;
+@@
+
+(
+* if (size cmp E1 || ...)@p {
+ ...
+* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+* kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...)
+ ...
+ } else {
+ ...
+* E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+ ...
+ }
+|
+* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+* kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...)
+ ... when != E = E1
+ when != size = E1
+ when any
+* if (E == NULL)@p {
+ ...
+* E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+ ...
+ }
+|
+* T x = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+* kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...);
+ ... when != x = E1
+ when != size = E1
+ when any
+* if (x == NULL)@p {
+ ...
+* x = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+ ...
+ }
+)
+
+@kvfree depends on !patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+* if (is_vmalloc_addr(E))@p {
+ ...
+* vfree(E)
+ ...
+ } else {
+ ... when != krealloc(E, ...)
+ when any
+* \(kfree\|kzfree\)(E)
+ ...
+ }
+
+@depends on patch@
+expression E, E1, size, node;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier flags, x;
+type T;
+@@
+
+(
+- if (size cmp E1)
+- E = kmalloc(size, flags);
+- else
+- E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- if (size cmp E1)
+- E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- else
+- E = vmalloc(size);
++ E = kvmalloc(size, GFP_KERNEL);
+|
+- E = kmalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+- E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (E == NULL)
+- E = vmalloc(size);
++ E = kvmalloc(size, GFP_KERNEL);
+|
+- T x = kmalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+- x = vmalloc(size);
++ T x = kvmalloc(size, flags);
+|
+- T x = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (x == NULL)
+- x = vmalloc(size);
++ T x = kvmalloc(size, GFP_KERNEL);
+|
+- if (size cmp E1)
+- E = kzalloc(size, flags);
+- else
+- E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- if (size cmp E1)
+- E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- else
+- E = vzalloc(size);
++ E = kvzalloc(size, GFP_KERNEL);
+|
+- E = kzalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+- E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (E == NULL)
+- E = vzalloc(size);
++ E = kvzalloc(size, GFP_KERNEL);
+|
+- T x = kzalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+- x = vzalloc(size);
++ T x = kvzalloc(size, flags);
+|
+- T x = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (x == NULL)
+- x = vzalloc(size);
++ T x = kvzalloc(size, GFP_KERNEL);
+|
+- if (size cmp E1)
+- E = kmalloc_node(size, flags, node);
+- else
+- E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- if (size cmp E1)
+- E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- else
+- E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- E = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+- E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (E == NULL)
+- E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- T x = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+- x = vmalloc_node(size, node);
++ T x = kvmalloc_node(size, flags, node);
+|
+- T x = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (x == NULL)
+- x = vmalloc_node(size, node);
++ T x = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- if (size cmp E1)
+- E = kvzalloc_node(size, flags, node);
+- else
+- E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- if (size cmp E1)
+- E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- else
+- E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, GFP_KERNEL, node);
+|
+- E = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+- E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (E == NULL)
+- E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, GFP_KERNEL, node);
+|
+- T x = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+- x = vzalloc_node(size, node);
++ T x = kvzalloc_node(size, flags, node);
+|
+- T x = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (x == NULL)
+- x = vzalloc_node(size, node);
++ T x = kvzalloc_node(size, GFP_KERNEL, node);
+)
+
+@depends on patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+- if (is_vmalloc_addr(E))@p
+- vfree(E);
+- else
+- kfree(E);
++ kvfree(E);
+
+@script: python depends on report@
+p << kvmalloc.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING opportunity for kvmalloc")
+
+@script: python depends on org@
+p << kvmalloc.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING opportunity for kvmalloc")
+
+@script: python depends on report@
+p << kvfree.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING opportunity for kvfree")
+
+@script: python depends on org@
+p << kvfree.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING opportunity for kvfree")
--
2.26.2

Next message: Limonciello, Mario: "RE: Keyboard regression by intel-vbtn"
Previous message: Tejun Heo: "Re: [PATCH V6 1/2] percpu_ref: reduce memory footprint of percpu_ref in fast path"
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